1. Field of the Invention
This invention relates to a composition suitable for moderating the growth of graminaceous plants. Accordingly, a primary object of the present invention is to provide a composition suitable for moderating the growth of graminaceous plants by shortening the length of plants, moderating the tillers and advancing the earing period.
Generally, graminaceous plants are tillering crops, and to moderate the tillering for the purpose of agricultural production is significantly meaningful to get an increased harvest.
2. Description of the Prior Art
In the specific situation of the rice-plant taken as an example of typical graminaceous plants, many tillers occur, but the ears are not inserted on all of them and some of them wither by the earing period. Such tillering is called non-available tillering which are very often observed among the 1st, 2nd and 3rd tillers occurring at high nodes of culms.
The occurrence of these non-available tillers varies, depending upon environmental conditions and cultivation methods, and the tillers are easy to develop in a warmer and more sufficiently fertilized place.
In a modern cultivation method for an increased harvest, it is important to secure powerful tillers as early as possible on which a necessary and sufficient amount of the ears (numbers of ears per unit area) will be inserted to get a desirable harvest, and to control the growth of subsequent non-available tillers. The rate of fertilizer application is recomended as a basal dressing, a foliar fertilizer or an ear manuring. Practically, popular cultivators use an excessive amount of fertilizer, resulting in the growth of non-available tillers. By these non-available tillers' growth, ears are made small-sized, culms are made weak to be liable to fall, and diseases in the latter period of growth, such as blighting disease easily occur, and as a result, the above harmful influences result in a decrease in a yield.
In the study leading to the present invention, a wide variety of chemicals capable of moderating the tillers of graminaceous plants, controlling the unnecessary height of plants and undesired extension of stems and leaves to get an increased yield have been studied. As a result of the study, it has been found that a composition comprising, as an effective ingredient, a sulfonate or a sulfuric ester having the following formula (I) can achieve the objective of the invention discussed above. EQU R.sup.1 --SO.sub.3 M (I)
in the formula (I) R.sup.1 represents an alkyl or alkenyl group having 8 to 20 carbon atoms, an alkylaryl group containing an alkyl group of 8 to 20 carbon atoms, the residue of succinic acid esters represented by the formula, ##STR2## wherein R.sup.2 and R.sup.3 represent an alkyl group of 1 to 18 carbon atoms or an alkylaryl group containing an alkyl group of 1 to 18 carbon atoms, or the group of R.sup.4 O--, wherein R.sup.4 represents an alkyl group of 8 to 20 carbon atoms or an alkylaryl group 8 to 20 carbon atoms; and M represents an organic or inorganic salt.